This invention relates to a hydraulic brake booster assembly and more particularly to one having a manually operable control valve to control pressure increase in the booster for attaining the available braking pressure in the brake wheel cylinders of the vehicle.
It has been the practice in the art that means is employed in order to hold-off a reaction force to the pedal so that a proper brake feel is transmitted to the vehicle operator at an initial stage of actuation of the booster. The means may be of such type as disclosed by U.S. Pat. No. 3,699,680 in which is mounted a cylinder and reaction piston assembly together with a compressed spring to preload the assembly. This arrangement is considered to be deficient in that, the booster is structurally complicated.